Surge arrester



June ll, 1929. l, s. CROCKER SURGE ARRESTER Filed March '7, 1923 In\/entor- ITW/ing S.C\^ocker, by ,MPW

His 'Attorney Patented June 11, 1929.

UNITED STATES PATENT OFFICE.v

IRVING S. CROCKER, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SURGE ARRESTER.

Application filed March 7,

My invention relates to surge arresters and is particularly adapted tor the protection et incaiulescent lamps on series lighting circuits.

lVith the advent of incandescent lamps having filaments o'li materials having a positive temperature cocliicieut, such for example, as tungsten or tantalun'i, and their use in such circuits in lieu olE carbon filament lamps, a serious ditticulty has arisen because of the burning out ot lamps due to surges on the line. The older form ot' carbon filament lamps was .not so sensitive to sudden increases in current inasmuch as the carbon ot their filaments had a. nearly zero or a negative tenxperature coetlicient. Alamp with a filamenthaving a positive temperature coefficient such as tungsten or tantalum is, however, extremely sensitive to variations in current, hence abnormal increases in. current due to surges in the line have 'frequently resulted in burned out lamps. Not only are the incandescent lamps lirequently damaged by such surges, but other devices and the line itself are 'frequently injured. Therc, for example, a rectiiier tube is arranged to supply a constant current circuit. il the rectifier tube roes bad there is usually a period ot time during which the circuit is flashing continually and any are lamps which. may be on the circuit are subjected to a terrific pounding which many times results in their destruction. Such surges are particularly apt to damage the line where cables are used since the insulation of the aibles is broken down.

An object oit my invention is to provide a simple and reliable arrangement which will prevent damage to incandescent lamps on circuits ot the class described, prevent damage to the line, prevent damage to other apparatus connected to the line from line surges ot the character described, and also prevent injury to the line and the appa atus connected thereto from abnormal voltages even thou ;'h the current in the line is normal.

My invention will be better understood by reference to the. accompanying specification and drawing and its scope will be pointed out in the apiiended claims.

The single figure of the drawing is a dia- `cran'm'iatic representation of my invention, showing the apparatus and the connections thereof to the distribution circuit.

Referring tothe drawing, 1 and 2 are the. two sides of a load circuit which for example may be ted from a series mercury are recapparcn t.

1923. Serial NO. ($23,532.

tifier or from a constant current trans former of the type shown for example in the patent to Elihu Thomson, No. 516,846, and in this circuit are shown series connected are lamps El and incandescent lamps al1. A short circuiting,l plug,l switch 5 and secondary plujr swi tchcs (3 and 7 may be used to control the lightingY circuit. A horn gap arrester comprising a pair ot horns 8 carried by a pair ot' rods f) is connected across the line in parallel with the lamps by conductors l() and 11. The rods 9 also carry a pair of spark gap terminals 1Q and 13, one oit which, namely,.terminal l5, is shown insulated by a bushing 1l Ytrom the rod by which it supported. These terminals are also connected across thc line in parallel with the lamps 3 and 4l; as shown. A lever 15, having' one end pivolally mounted at 1G, carries at its itrce end a pair o'l. upstmilling1 ears 17 and pivoted to these ears a wedge shaped member 18 adapted when the lever is in its raised position to male Contact with both horns 8 oit the horn gap arrester. The lever normally gravitates to its lowered or inoperative position a d tor actuating the lever to raise it to a position short circuiting the horn gap, an electro]uagfnet including a plunger 19 and solenoid 20 provided, the solenoidv beingconnected in series with the conductor 2 at a point between the points ol connection thereto ot the horn `rap arrester and the spark gap.

Ylhc operation ot the device will be readily lVhen the current. in the rectiliciil or transformed circuit increases to an execs` sive amount due to a sin-ge in the main line, the lever 15 is actuated by the plunger l) and solenoid 2O to bring the member 1S into snort Circu'itingl position across the horn gap arrester. The lamps sl are thus shunted and are elllectively protected 'trom the excessive current. As soon as the short circuit is established, however, the solenoid, being;` also shunted, becomes deenergized and allows 'the lever to drop to its normal position. Supposing' l'or example that the coils ol the rectifier trans'lormer or the, constant current transformer are separated a distance correspending' to the normal full load current, the increased repulsion between the two coils when the surge occurs forces the floatingl coil away, but the arc will hold at the horn `rap until the coil has reached its short circuit position. The arc then breaks a ud the `floating coil thereupon resumes its normal load position, the arc and incandescent lamps in turn resuming their normal operation. Thus the entire operation takes place automatically, the lamps are fully protected from the effects of the surge and after the surge has passed the apparatus is ready to take care of another surge Without requiring any manipulation by an operator.

The spark gap between terminals 12 and 13 functions to pass a high voltage which may be produced on the line unile the current is yet normal. Such voltage upon jumping thc spark gap Will pass through the solenoid and back to the rectiier or constant current machine. The resulting` abnormally high current, produced by reason o1 the relative position oi the coils at that time, will effect the operation ot the short circuitingl lever, the short circuit being subsequently removed and the arc thus drawn extinguished in the same manner as before.

It Will thus be seen that I have provided a device Which will automatically protect from the evil effects of surges lighting circuits o the character described employing incandescent lamps Whose filaments are particularly susceptible tQsuch surges and While I have described only one embodiment ot my invention, I do not Wish to be limited to the particular form shown and described as it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in the appended claims.

l/Vhat I claim as new and desire to secure by Letters Patent of the United States, is:

l. In combination in an electric system, a line adapted to be connected to a source ot current, an electric device connected across said line and operated by current supplied over said line, an electromagnet in series with said line, a spark gap across said line, and means under the control of said electromagnet for mechanically short circuiting,l said spark gap and said line.

2. In combination in an electric system, a` line adapted to be connected to a source ot current, an electric device connected across said line and operated by current supplied over said line, an electromagnet in series with said line, a spark gap across said line, means under the control of said electromagnet for mechanically short circuiting said spark gap, and a second spark gap across said line, said spark gaps being' of different character.

In Witness whereof, I have hereunto set my hand this 2nd day of March, 1923.

IRVING S. CROCKER. 

